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Unit 1Chapter 2-pg38
Matter and ChangeChemistry 334
Essential Question:
How do chemists classify matter?
Section 2.1Properties of Matter
Describing MatterKC: How can Properties be used to describe
matter?
A: Properties used to describe matter can be classified as ether extensive or intensive.
Extensive PropertiesA property that depends on the amount of
matter in a sample.
Examples of extensive properties:
Mass—the amount of matter an object contains.
Volume—the measure of the space occupied by an object.
Intensive Properties:A property that depends on the type of matter in
a sample, not the amount.
ExamplesHardnessOdorConductivityState of matter
*******What it is made of******
Identifying SubstancesKC: Why do all samples of a substance have the
same intensive properties?
Every sample of a given substance has identical intensive properties because every sample has the same composition.
SubstanceMatter that has definite and uniform
composition.
AKA: Pure substance
Examples: AuAgNaClCH4
NaCl vs. NaCl Water (H2O)Q: Is salt water a pure substance????
INDEX CARD CHALLENGE!!!!
INDEX CARD CHALLENGEWithout talking, find someone who has a
different answer that you
IDK—does not count as an answer!!!
Explain why you chose this answer.
The AnswerNaCl is a pure substance
Salt water is not It can have variable composition
Physical PropertiesPhysical property—any quality or condition of a
substance that can be observed without changing the substance’s composition.
Examples:StateMpBpColor
States of matter:KC: What are 3 states of matter?
A: Three states of matter are solid, liquid, gas.
SolidDefinite shape
Definite volume
Not easily compressed
LiquidIndefinite shape
Definite volume
Not easily compressed
GasIndefinite shape
Indefinite volume
Easily compressed
Three States of Matter
VaporDescribes the gaseous state of a substance that
is generally a liquid or solid at room temperature.
Physical ChangesKC: How can physical changes be classified?
A: Physical changes can be classified as reversible or irreversible.
ReversiblePhase changes
MeltingFreezing SublimationBoilingCondensation
IrreversibleBreaking
Tearing
Smashing
Cutting
Section 2.2 MixturesPage 44
Classifying MixturesKC: How can mixtures be classified?
A: Mixtures can be calssified as either hetterogenous or homogenous.
MixtureA combination of two or more
pure substance.
Can be made with different combinations of solid, liquids and gasses.
2 Types of mixtures1. Homogenous
2. Heterogenous
Heterogeneous MixtureNot the same through out
More than one phase
(distinguishable parts) ie:
Chicken noodle soup Chex mix
Homogenous mixtureUniform composition; same through out
AKA: SolutionOnly one phase ie:
Salt waterTeaOlive oilVinegarAlloy
Separating MixturesKC: How can mixtures be seperated?
A: Differences in physical properties can be used to separate mixtures.
5 ways to separate mixtures
1. Filtration
2. Distillation
3. Crystallization
4. Sublimation
5. Chromatography
FiltrationA technique which uses a pours barrier to
separate a solid from a liquid
DistillationA separation technique that is based on the
differences in the boiling points of the mixed substances
CrystallizationA separation technique that results in the
formation of pure solid particles of a substance from a solution containing the dissolved substance.
SublimationThe process during which a solid changes to a
vapor without going through the liquid phase
ChromatographyA technique that separates the components of a
mixture (aka-mobile phase), based on the ability of each component to be drawn across the surface of another material (aka-stationary phase).
Section 2.3Elements and Compounds
Distinguishing Elements and Compounds
KC: How are elements and compounds different?
A: Compounds can be broken down into simpler substances.
Examples of elementsCa
Na
H
Periodic TableOrganizes the elements into a grid of horizontal
rows (aka-periods) and vertical columns (aka- groups/families).
CompoundsTwo or more elements combined chemically
Breaking Down Compounds
Compounds can be broken down by chemical change
This process usually requires a an external energy source, such as heat or electricity
Properties of CompoundsThe chemical and physical characteristics of a
compound is very different than that of its constitute parts.
Example:K + I KI
Potassium & Iodine VS Potassium iodide
Potassium A light silver metal that reacts with water
IodineA black solid that changes to a purple gas at
room temperature.
Potassium iodide A white salt
Distinguishing Substances and Mixtures
KC: How can substances and mixtures be distinguished?
A: If the composition of a material is fixed, the material is a substance. If the composition of the substance may vary, the material is a mixture.
Classification of matter
Ex: chex salt NaCl Na
mix water
(AKA: solutions)
Symbols and formulasKC: What do chamists use to represent elements
and compounds?
A: Chemists use chemical symbols to repersent elenents and chemical formulas to represent compounds
Chemical SymbolOne or two letters used to represent the name of
an element.
Chemical Compounds
Section 2.4Chemical Reactions
Chemical ChangesKey Concept: What always happens during a
chemical change?
Answer: During a chemical change, the composition of matter changesExample
combustion reaction
Examples:Fe to Rust
Respiration
Combustion (candle burning vs. wax melting)
Words that indicate a chemical change:
-Decompose -Ferment -Tarnish
-Oxidize -Burn -Rust
-Corrode -Rot -Explode
Chemical Properties=The ability (or inability) of a
substance to combine with or change into one or more substances.
Chemical ChangeOne or more substances changes into one or
more new substances.
AKA: Chemical reaction
Mg + HCl H2 + MgCl
Reactants The substance that are to be transformed.
ProductThe substance(s) that are made
Recognizing Chemical Changes
Key Concept: What are the 4 possible clues that a chemical change has taken place?
Answer: Possible clues that a chemical reaction has taken place include: transfer of energy (heat or light), a change in color, the production of gas, or the formation of a precipitate.`
Precipitate=The production of a solid.
Conservation of MassKey concept: How are the masses of the
reactants and the masses of the products of a reaction related?
Answer: During any chemical reaction the mass of the reactants is always equal to the mass of the products.
Law of Conservation of Mass:
Massreactants=Massproducts
Practice Problems2Mg + O2 2 MgO
Mass of Magnesium
(g)
Mass of Oxygen(g)
Mass of Magnesium oxide
(g)
5 3.3 8.3
6.5 A 10.8
13.6 9 B
C 12.5 31.5
Words that indicate a chemical change:
-Decompose -Ferment -Tarnish
-Oxidize -Burn -Rust
-Corrode -Rot -Explode
Physical Changes=A change which alters a
substance without changing its composition.
Examples of physical changes:
CuttingBrakingPhase Change=transition of
mater from one state to another.
Chemical changes vs. physical changes
Physical Changes
Alters a substance without changing its composition (arrangement of its atoms)
Does NOT change the arrangement of atoms
SAME substance!
Chemical Changes
Alters a substance by changing its composition (arrangement of its atoms)
DOES change the arrangement of atoms
NEW substance made!
Chemical/Physical changes Foldable